The present invention relates generally to electronic circuits, and more particularly, to a host device that communicates with an embedded multi-media card (eMMC) device.
Portable electronic devices, such as portable computers, cell phones, digital cameras, wearable devices, and the like, generally include an embedded multi-media card (eMMC) device for data storage. Such eMMC devices are embedded within the corresponding portable electronic device, and include a flash memory for storing data. The portable electronic devices further include an embedded host device that performs various memory access operations on the eMMC device.
FIG. 1 shows an example of a conventional host device in communication with an eMMC device. More particularly, FIG. 1 shows an integrated circuit (IC) 100 including a conventional host device 102 in communication with an eMMC device 104. The IC 100 is embedded within an electronic device (not shown), such as one of the devices listed above. The host device 102 may comprise a microprocessor, a microcontroller, an application specific integrated circuit (ASIC) processor, a central processing unit (CPU), and the like. The host device 102 includes a host controller 106 that enables the host device 102 to communicate with the eMMC device 104 by way of a communication interface 108. The communication interface 108 includes a bidirectional command channel 108A, a unidirectional clock channel 108B, and a bidirectional data bus 108C including eight data channels.
The host device 102 is connected between a supply voltage VCC and ground GND. The host controller 106 is a dedicated peripheral of the host device 102 that has dedicated pins (not shown) for communication with the eMMC device 104.
The eMMC device 104 is connected between the supply voltage VCC and ground GND. The eMMC device 104 includes an eMMC device controller 110 and a memory array 112. The eMMC device controller 110 is a dedicated peripheral that enables the eMMC device 104 to communicate with the host device 102 by way of the communication interface 108. The eMMC device controller 110 has dedicated pins (not shown) for communicating with the host device 102. The eMMC device 104 further includes a reset terminal RST for receiving a reset signal. The memory array 112 is a flash memory that stores data.
The host device 102 transmits various commands to the eMMC device 104 for performing various memory access operations, by way of the host controller 106 and the bidirectional command channel 108A. Examples of the commands include data-read, data-write, data-erase, format eMMC, and the like. The host device 102 further transmits a clock signal to the eMMC device 104 by way of the host controller 106 and the unidirectional clock channel 108B. The clock signal synchronizes the eMMC device 104 with the host device 102.
The eMMC device 104 transmits a response to each command received from the host device 102 by way of the eMMC device controller 110 and the bidirectional command channel 108A. Based on the response, the host device 102 performs the corresponding memory access operation on the eMMC device 104. For example, based on the response to the data-write command, the host device 102 transmits write-data to the eMMC device 104, and based on the response to the data-read command, the host device 102 receives read-data from the eMMC device 104.
As portable devices become smaller, it would be advantageous to be able to reduce the size of the host device.